1. Field of the Invention
This invention pertains to a clean air cabinet. More particularly, this invention pertains to a clean air cabinet including novel construction for improved compactness, manufacture and performance.
2. Background of the Invention
In the prior art, clean air cabinets are widely used in laboratory environments. Biological safety cabinets are a unique segment of clean air equipment used to protect an operator from contamination with bacteria, virus, chemicals and toxic particulates.
An example of a clean air cabinet is disclosed in commonly assigned U.S. Pat. No. 4,832,717. That patent teaches a clean air cabinet which utilizes two high efficiency particulate air (HEPA) filters. The use of two HEPA filters is common is clean air cabinets. Commonly, one of the HEPA filters is used to filter air being passed from a blower into a work chamber. The second HEPA filter is used to filter air drawn out of the work chamber and passed to the environment.
In the manufacture of clean air cabinets, cost control is very important. The use of two HEPA filters adds significantly to the cost of a cabinet. Further, when a cabinet is not being used and its blower is not operating, contaminants may enter the cabinet. It is desirable to provide a clean air cabinet which is low cost and which avoids contamination during disuse of the cabinet.